This can be accomplished a few ways. My preferred way is to use the
interactive clustering method. The report function of interactive clustering will show you the clusters of a given size (or larger) for any t-value (and related p-value) that you wish. If you then wish to show each cluster as a different color, use the SaveMsk button to save your clusters as a mask. Each cluster will receive a different number corresponding to its rank in the cluster report. You can open your Cluster mask as the overlay, drop your t-value down to zero and you will be able to see each cluster as a separate color.